Altitude Sickness: Prevention & Treatment (2026)

High altitude travel to places like Cusco, Peru, La Paz, Bolivia, or the Everest Region can turn your dream trip into a nightmare if you're not prepared for altitude sickness. The actual problem isn't just discomfort; it's a potentially life - threatening condition that can derail your entire itinerary. The one - line answer to enjoying high - altitude destinations safely is gradual ascent and proactive prevention, primarily through smart acclimatization and, for some, medication.

This guide is for anyone planning to visit destinations above 2,500 meters (8,000 feet), especially those flying directly into high - altitude cities like Cusco (3,400m / 11,150ft) or La Paz (3,640m / 11,942ft). Skip this if your trip stays below 2,500 meters or if you're undertaking a very gradual, multi - week ascent from sea level.

• Acute Mountain Sickness (AMS). A common, mild form of altitude sickness characterized by headache, nausea, fatigue, and dizziness, usually developing within 6 - 12 hours of arrival at high altitude.
• High Altitude Cerebral Edema (HACE). A severe and potentially fatal form of altitude sickness where fluid accumulates in the brain, leading to confusion, ataxia, and altered consciousness.
• High Altitude Pulmonary Edema (HAPE). A severe and potentially fatal form of altitude sickness where fluid builds up in the lungs, causing shortness of breath, cough, and chest tightness.
• Acclimatization. The physiological process by which your body adjusts to the reduced oxygen levels at high altitudes over several days.
• Acetazolamide (Diamox). A prescription medication used to prevent and treat altitude sickness by accelerating the acclimatization process.

1. Consult Your Doctor for Acetazolamide. At least 2 - 4 weeks before your trip, discuss altitude sickness prevention with your doctor, especially if you have pre - existing conditions. Request a prescription for Acetazolamide (Diamox) if you plan on rapid ascent or have a history of AMS. The typical preventative dose is 125mg twice daily, starting 24 hours before ascent.
2. Plan a Gradual Ascent Itinerary. Prioritize a slow climb. If flying into Cusco, spend 1 - 2 nights in the Sacred Valley (e.g., Urubamba or Ollantaytambo, ~2,800m / 9,186ft) before heading to the city itself. For La Paz, consider flying into El Alto (4,058m / 13,313ft) and descending immediately to the lower parts of the city, or better yet, take a bus from a lower - elevation city like Puno, Peru.
3. Stay Hydrated and Avoid Alcohol/Heavy Meals. Upon arrival at altitude, drink at least 3 - 4 liters of water daily. Avoid alcohol for the first 48 hours entirely, as it dehydrates and can exacerbate symptoms. Stick to light, carbohydrate - rich meals; heavy, fatty foods are harder to digest and can contribute to nausea.
4. Rest on Arrival and Limit Exertion. Do not attempt strenuous activity on your first day at altitude. Even a gentle walk can feel like a marathon. Rest at your accommodation, unpack slowly, and listen to your body. Save major sightseeing and treks for days 2 and 3.
5. Monitor for Warning Signs and Communicate. Be vigilant for symptoms: headache, nausea, dizziness, unusual fatigue, or trouble sleeping. If symptoms worsen despite rest, or if you develop confusion, severe shortness of breath, or a cough, alert your travel companions or local guide immediately. Use a pulse oximeter (available for about $20 on Amazon) to track your blood oxygen saturation (SpO2) if you have one – readings below 80% should be taken seriously at high altitudes.

• Start Acetazolamide 24 hours before you ascend if prescribed – don't wait until you feel sick.
• Carry a small, portable pulse oximeter (e.g., Zacurate 500DL, ~$25) to monitor your blood oxygen saturation, especially if feeling unwell.
• Research clinics and hospitals at your high - altitude destination before you go; know where to get help if needed.
• Learn a few basic phrases in the local language (e.g., 'altitude sickness,' 'headache,' 'doctor') to communicate your symptoms effectively.
• Plan a flexible itinerary that allows for extra acclimatization days if you feel unwell; don't rush it.
• Drink plenty of water and herbal teas, especially mate de coca in Andean regions, but understand it's not a substitute for proper acclimatization.

• Don't fly directly into extreme altitudes (e.g., Lhasa, Tibet, or Everest Base Camp) without a multi - day buffer at an intermediate elevation first; rapid ascent is the biggest risk factor.
• Avoid pushing yourself with strenuous activity (like hiking the Inca Trail) on your first 1 - 2 days at altitude; give your body time to adjust.
• Don't ignore worsening symptoms, especially a persistent cough, severe headache, or confusion; these could indicate HAPE or HACE.
• Never take sleeping pills or strong sedatives at high altitude without a doctor's explicit approval; they can suppress breathing and worsen altitude issues.
• Don't consume alcohol or large amounts of caffeine for the first 24 - 48 hours; both dehydrate and can mask or worsen symptoms.
• Don't rely solely on over - the - counter pain relievers (like ibuprofen) to manage severe altitude headaches; they only treat symptoms, not the cause.

• Pack a small bottle of Pepto - Bismol chewables – altitude can wreak havoc on your digestive system, and nausea is a common AMS symptom.
• Even if you're fit, you're not immune; altitude sickness affects people indiscriminately, regardless of physical condition or age. An ultra - marathoner can get hit harder than a couch potato.
• If you're doing a multi - day trek (like to Everest Base Camp), carry a personal water filter (e.g., Sawyer Squeeze, ~$30) to ensure constant, safe hydration from local sources.
• Book accommodations with heating options if traveling to cold, high - altitude regions; staying warm conserves energy and helps your body acclimatize.
• For places like the Everest Region, bring a broad - spectrum antibiotic like Azithromycin (prescription needed) as respiratory infections are common and can complicate altitude issues.
• Consider an overnight train from a lower elevation to a high - altitude city if available; the slower ascent is often better than flying direct.
• Always carry a small headlamp – even if you're in a city, power outages can happen, and navigating in the dark at altitude is disorienting.
• If you're prone to nosebleeds, bring a small tube of nasal gel (like Ayr Saline Nasal Gel) to keep nasal passages moist in dry, high - altitude air.
• In places like Cusco, many hotels offer oxygen tanks for guests; ask about this when booking and don't hesitate to use it for temporary relief.
• Take a small bag of hard candies or lozenges – the dry air at altitude can give you a persistent cough, and sucking on something can provide relief.